1. Field of the Invention
The present invention is related to a process for preparing divinylarene dioxides, such as for example divinylarene dioxides derived from divinylbenzene. More specifically, the present invention relates to a process for preparing a divinylarene dioxide by utilizing a chlorohydrin route.
2. Description of Background and Related Art
Divinylarene dioxides, particularly divinylbenzene dioxide (DVBDO) and others which are derived from divinylbenzene (DVB) are a class of diepoxides which can be used as either reactive diluents or the main epoxy resin matrix in epoxy thermoset formulations. DVBDO itself has a very low liquid viscosity (for example less than about 20 centipoise [0.02 Pa-s]) making DVBDO especially useful in the preparation of low viscosity epoxy formulations. The epoxy formulations made from DVBDO are useful as intermediates in the production of various other products. For example, epoxy formulations made from DVBDO are suitable for use in the fields of coatings, composites, and molding compositions.
In general, the production of divinylarene dioxide can be accomplished by a variety of different methods. For instance, some of the prior art methods include: (1) oxidation by peroxy carboxylic acids; or (2) oxidation by hydrogen peroxide with a catalyst. For example, M. Worzakowska, J. Appl Poly Sci (2007) vol. 103, 462-469, discloses epoxidizing DVB by a method using acetonitrile-hydrogen peroxide with magnesium oxide catalyst and greater than a 4 fold molar excess of hydrogen peroxide to olefin. U.S. Pat. No. 2,977,374 also discloses epoxidizing DVB using peracetic acid in ethyl acetate and reports a DVBDO yield of 49%.
Hoppf et al., Helvetica Chim Acta (1957) 40, 274 teaches the use of chlorohydrins and base to produce DVBDO; however, the chlorohydrins are generated by the reduction of chloroacetylbenzenes with lithium aluminium hydride.
None of the heretofore known processes disclose the successful preparation of divinylarene dioxides using hypochlorous acid to produce the chlorohydrin, followed by base treatment to produce the epoxide at high yields.